How do you evaluate #x( 5x - 4) ( 2x - 3)#?

2 Answers
Jun 22, 2018

#10x^3 - 23x^2 + 12x#

Explanation:

First, use the distributive property (shown below) to simplify #x(5x-4)#:
cdn.virtualnerd.com

Following this image, we know that:
#color(blue)(x(5x-4)) = (x * 5x) + (x * -4) = 5x^2 - 4x#

Put that back into the expression:
#(5x^2 - 4x)(2x-3)#

Now use the distributive method FOIL (shown below) to simplify the rest of the expression:
enter image source here

Following this image, we can multiply it out.

The #color(teal)("firsts")#:
#color(teal)(5x^2 * 2x) = 10x^3#

The #color(indigo)("outers")#:
#color(indigo)(5x^2 * -3) = -15x^2#

The #color(peru)"inners"#:
#color(peru)(-4x * 2x) = -8x^2#

The #color(olivedrab)"lasts"#:
#color(olivedrab)(-4x * -3) = 12x#

Combine them all together to get:
#10x^3 - 15x^2 - 8x^2 + 12x#

We can still combine the like terms #color(blue)(-15x^2)# and #color(blue)(-8x^2)#:
#10x^3 - 23x^2 + 12x#

Hope this helps!

Jun 22, 2018

#10x^3-23x^2+12x#

Explanation:

#x(5x-4)(2x-3)=x(10x^2-8x-15x+12)#
#x(10x^2-23x+12)=10x^3-23x^2+12x#